Study mechanisms of T-cell mediated cytotoxicity at the molecular level using as a model system the specific killing of allogeneic tumor cells by immune peritoneal exudate cells. Specifically: determination of the importance of composition, organization, and mobility of target cell membrane components on susceptibility to T-cell mediated cytotoxicity; determination of the effects of cytotoxic T-cells on target cell membranne lipids; and determination of the effects of various agents on the organization and mobility of target cell and effector cell membrane lipids. The CHY and EL4 tumor cell lines will be used; spin labelling will be applied to studying cell-cell interaction.